Ink seal means for rotary intaglio printing mechanism



April 5, 1960 E. A. COUDRIET INK SEAL MEANS FOR ROTARY IN'IAGLIO PRINTING MECHANISM Filed Aug. 19, 1957 3 Shets-Sheet 1 H km FIG. 2.

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April 5, 1960 v E. A. COUDRIET INK SEAL MEANS FOR ROTARY INTAGLIO PRINTING MECHANISM 3 Sheets-Sheet 2 Filed Aug. 19, 1957 INVENTOR. [ammo/4. Comm/7, BY

April 5, 1960 E. A. COUDRIET INK SEAL MEANS FOR ROTARY INTAGLIO PRINTING MECHANISM 3 Sheets-Sheet 3 Filed Aug. 19, 1957 FIG.6.

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nited States Patent INK SEAL MEANS FOR ROTARY INTAGLIO PRINTING MECHANISM Edward A. Coudriet, Henrico County, Va., assignor to The Inta-Roto Machine Company, Inc., Henrico County, Va., a corporation of Virginia Application August 19, 1957, Serial No. 678,783

7 Claims. (Cl. 101157) This invention relates in general to inking systems for printing apparatus and more particularly to improvements in an ink applicating system for rotogravure or intaglio printing apparatus.

In modern printing methods, great emphasis is placed upon speed of operation and press speeds have been greatly increased in recent years. Attendant to this increase in printing speed, several difficulties have arisen, particularly with rotary printing, and more especially with intaglio printing. With higher rotary printing speeds, it is necessary, because the paper is traveling faster, to utilize inks which have very rapid drying characteristics. With engraved printing cylinders, using conventional applicator methods, it is possible for ink, having the proper drying characteristics, to dry within the depressions or reliefs in the printing plate, resulting in poor quality of printing. Further, with greater press speeds, difficulty arises from the tendency of the ink to be flung from the printing cylinder, which causes a variance in the distribution of ink within the reliefs or depressions in the printing plate.

it is, therefore, the primary objective of the present invention to provide an ink applicator system, especially for rotary intaglio presses, wherein the ink is applied to the printing cylinder in measured amounts and retained thereon in proper condition during the printing operation without excessive drying which would tend to clog the printing plate and reduce the quality of printing.

it is another object of the invention to provide an ink applicator system that is effective in preventing the ink from being flung from the printing cylinder during the printing operation.

A further object of the invention is to provide an ink applicator system for rotogravure printing apparatus having simplicity of design, economy in construction and efficiency in operation.

Briefly, an ink applicator system for rotary intaglio printing apparatus, according to the present invention, comprises applying ink completely over the surface of the cylinder immediately behind the nip of the engraved printing cylinder and the pressure roll while the printing cylinder is rotating at high speeds, metering the quantity of ink on the cylinder, maintaining the metered ink in intimate contact with the cylindrical printing surface completely therearound to the doctor blade, and preventing flinging of the metered ink from the cylinder surface while inhibiting evaporation or drying of the ink. The apparatus, according to the invention, comprises a troughlike ink reservoir disposed at one side of a printing cylinder with the open side of the trough facing the cylindrical surface in close juxtaposition, and a non-scratching flexible ink impervious sheet extending from the trough reservoir beneath and in close proximity to the printing cylinder and terminating at the opposite side thereof at the doctor blade or closely adjacent the nip between the printing cylinder and the pressure roll. The trough reservoir is continuously flooded with ink so as to apply ink 'freely over the surface of the printing cylinder and which is carried therefrom, byrotation of the cylinder, through the region covered by the sheet. The trough is provided with flexible, non-scratching, metering and splash blades at the bottom and top thereof and selectively spaced from the printing surface. The sheet is adjustably positioned so as to be selectively spaced concentrically with respect to the cylinder to prevent ink from being flung from the cylinder and at the same time to isolate the ink on the cylinder from the surrounding atmosphere and retard evaporation of ink solvents, thus retaining the same in proper printing condition.

The novel features that are considered characteristic of the invention are set forth with particularlity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of specific embodiments when read in connection with the accompanying drawings, wherein like reference characters indicate like parts throughout the several figures and in which:

Figure l is a perspective view showing the component parts of one form of ink applicator structure constructed in accordance with this invention operatively associated with a printing cylinder;

Fi ure 2 is a vertical section through the assembly and illustrating the relationship of the component parts with respect to a printing cylinder;

Figure 3 is an elevational view taken on the ink supply side of the assembly;

Figure 4 is a fragmentary view in perspective of the splash blade for the ink applicator;

Figure 5 is a sectional view taken through one end of the chamber forming body of the ink applicator and illustrating the construction of the end seals thereof;

Figure 6 is an end view of an ink applicator having a modified end closure, part of which is broken away for clarity of illustration, and V Figure 7 is an enlarged exploded view in perspective of the elements forming the end closure per se.

Referring now with particularity to the drawings, specifically to Figure 2, a typical rotary intaglio printing apparatus comprises an engraved printing cylinder 11 peripherally engaged by a pressure roll 43. An elongated web 44, usually paper, is run through the nip between the cylinder 13. and roll 43, normally passing around the roll 43 and other temperature-controlled rolls in tandem relation for drying the ink applied by the cylinder. Ink is usually applied to the cylinder 11 either by rotation thereof in a bath or by flooding the surface by an ink applicator 26, as by a spray behind the nip in which event sufficient ink is applied to ofiset the centrifugal flinging of the ink due to the speed of the roll. In the first instance, the rotation of the cylinder splashes and flings ink from the bath beyond the doctor blade 49 and smears the equipment and spoils the printing job. In the latter instance, there is a great deal of centrifugal flinging and high evaporation, a high percentage of ink being consumed with consequent increase in costs, and a certain amount of clogging of the engravings is inevitable. To reduce losses, careful and complete shielding is necessary and speed of operation is limited.

The foregoing defects are overcome by the present invention, the concept of which encompasses flooding the printing surface of the cylinder adjacent and behind the nip to fill the engraving and dissolve any residual ink therein, metering the ink after the flooding thereof to preclude the application of excessive quantities thereof, retaining the ink in intimate contact with the printing surface throughout the travel of the surface to the doctor blade and preventing the flinging of the ink from the cylindrical printing surface during the travel thereof.

This method has produced surprising results in that the web has been printed at a speed of 1000 feet per minute without the normally attendant damage and loss due to. high speed operation. Flinging of the ink. is eliminated, thereby making expensive and clumsy shielding unnecessary. Evaporationof the ink solvents has been greatly inhibited, reducing the quantity necessary and consumed during operation. Finally, drying of the ink Within the engraved recesses is precluded, thereby extending the life of the printing plate and decidedly reducing the necessary cleaning thereof.

The apparatus for performing the foregoing method, as best shown in Figures 1-3, basically comprises an ink applicator 26 in the form of an open trough 25 with the open side thereof juxtaposed to the printing surface of the cylinder 11 closely behind the nip with the pressure roll-43, and a sheet or apron 39 extending from the trough 25 substantially concentrically around the lower part of the cylinder in closely spaced relationship to the doctor'blade 40. This sheet 39 may be spaced from the cylindrical printing surface from to /2 inch, depending upon the viscosity of the ink, but normally the spacing will be between A; to /1 of an inch..

The sheet or apron 39 is of an ink-impervious material to preclude wasteful absorption or seepage of the ink and contact'of air with the ink volatiles. It is also of a non-scratchable material to prevent possible damage to the printing surface of the cylinder. Most importantly, it is flexible to enable adjustment thereof relative to the cylinderboth to accommodate cylinders of different diameter and inks of different viscosity. Finally, the material is substantially non-stretchable and has a high degree of strength to avoid sagging and variation during operation. A sheet of thermoplastic material, such as nylon, is well suited for the, purpose, and highly satisfactory results have been obtained with a sheet formed of the polyethylene terephthalate resin sold under the trade name Mylar which is outstandingly strong and chemically formed with oriented molecules of high tensile strength similar to Dacron.

Referring now to the drawings in greater detail, particularly to Figures l3, the printing cylinder 11 is suitably journaled in a conventional manner on a base frame and provided with drive mechanism (not shown) for rotating it at the requisite printing speed. For the purpose of supporting the applicator assembly 26' of this invention, a bar or other suitable support 12 is secured metering'blade 32 and associated securing strap 33. Each of the blades and 32 projects beyond its respective edges of the body 25 and extend toward the surface of the printing surface of the printing cylinder 11. The metering blade 32 is so disposed that its longitudinal metering edge 34 is closer to the cylinder 11 and it will be manifest that when the. ink is supplied to the chamber defined between the'trough 25 and printing cylinder 11, the chamber will become a reservoir of ink which floods the surface of the printing .plateand is metered onto the surface thereof by the distance the metering edge 34 of the blade 32 is spaced fromthe printing surface.

The metering space between the metering edge 34 of the blade 32 and the printing surface is varied according to the viscosity of the ink but normally the spacing is of the order of about of an inch. This metering space is selectively adjusted by means of. the screws 15 and their hand knobs 16, a rough adjustment of the trough 25 relative to the cylinder 11 having initially been effected by adjustment of the standards 13 and 14 about their supporting cross-rod 12. The. splash blade 39 is individually adjustable relative to the trough 25 and cylinder 11 by means of slots 30 therein, as shown in. Figure 4, and traversed. by'the screws securing the retaining strap 31. The splash blade 36 is usually spaced from the cylinder about A; of an inch, this spacing not being highly critical as there is relatively little splashing and this blade serves largely as a safeguard. Unlike the metal doctor blade 49, the splash blade 39 and especially the metering blade 32 are formed of a flexible, non-scratching material, such as nylon, or Mylar to preclude possible damage to the printing surface.

Fixed to the outer side of the channel support24 are a pair of depending support ears 35 and 36 which journal therebetween a split sheet support rod 37 having a T- handle 38 at one end thereof. Projecting through the split rod 37 is one end of the flexible sheet or apron 3% which is wrapped several times about the rod 37 to .securely anchor it and provide the necessary length for adjustment relative to the cyinder.

The opposite end of the sheet 39 is anchored behind the doctor bar 40 which to the base It and this bar carries a pair of uprights or standards 13 and 14 at one side of and respectively beyond the opposite ends of the printing cylinder 11. Each of the standards 13 and 14 carries an adjusting screw 15, on one end of which is mounted the hub 23 of a hand knob 16 secured to the screw by a pin 17.

Each screw 15 is provided with a threaded portion 13 having a collar 19 bearing against one side of the corresponding upright 13 or 14 and a journal portion 25! extending through a bore 21 through the upper end of the associated standard 13 ch14. The hub 22 of the knob 16 bears against the opposite side of the standard. Each of the screws EScarries a threaded nut 23, and is secured to the" corresponding end of a transverse support 24 which, 'as shown, may be of channel cross section. The support, in turn, carries the trough 25 which'preferably comprises a semi-cylindrical member of slightly greater lengththan the associated printing cylinder Hand which is carried by the support element 23 intermediate the nuts 23. Fixed to the semi-cylidrical. trough 25 is an ink supply manifold 27 having'branches' 23 leadinginto and communicating with the interior of the trough 25 and an inksupply line 29.

The upper edge of the trough 25 is provided with a splash blade 39 coextensive in length therewith and held on the body by. a suitablestrap 31 fastened to the trough 25 by. screws and sandwiching the blade 30 thereagainst.

On the lower inner edge of the "body 25-is-provided a is affixed to a support rod 41 carried by arms 42 which are swingably mounted at their remote ends on the base 10. The doctor bar engages the printing plateaalong a line parallel to and closely adjacent the nip between the printing cylinder 11 and the pressure roll 43, the paper passing between these two cylinders as shown. By turning the handle 38 of the sheet support rod-37, one end of the sheet is Wrappedor unwrapped upon or. from the rod to effectively shorten or lengthen the same. Disposed beneath the sheet 39 and printing cylinder 11 is a catch pan or basin 45 for the excess ink, this ink being continuously drained through the outlet 45 and recirculated to the manifold supply 29.

In operation of the press, the cylindrical printing plate of the'cylinder 11 is initially wetted with ink from the chamber formed by the trough 25 and meteredonto the printing surface as it passes the chamber. Excess ink on the plate gradually builds'a reservoir of ink, in-

dicated by the broken line R in Figure 2; in the space between the sheet 39 and cylinder 11 immediately below the trough 25. The sheet is so adjusted with respect to the cylinder as to maintain the platewet and prevent flinging of the ink therefrom due to the high speed of rotation of the cylinder, the ink escaping only from the edges of the sheet39 and drippinginto the pan 45. The

trough 25 and the cylinder define a substantially isolated chamber preventing rapid evaporation of the ink solvents and the disposition of the sheet 33 preserves this isolated atmosphere in addition to its property of preventing the ink from being flung from the cylinder/Consequently, particularly in view of the fact that the'doctor bar. is disposed closely adjacent-the. nip betweemthenwo cylinders 11 and 43, the ink is of proper consistency when it reaches the paper.

To prevent spillage of ink from the opposite ends of the trough 25, sealing means are provided in conjunction with this body, as shown most clearly in Figure 5. Atfixed to the opposite ends of the trough 25 are end disks 46 and carried thereby and inwardly thereof are the circular sealing plates 47. The sealing plates peripherally engage the inner cylindrical surface of the body 25 and are lightly spring pressed against the corresponding ends of the cylinder 11 by means of the compression springs 48 which may surround guide pins 49 and 50 carried by the end plates 46 and slidably received within apertures through the sealing plates 47. The sealing disks 47 are also preferably constructed from either nylon or Mylar.

During operation of the press, these component parts assure that the ink will be, to a greater extent, isolated from the surrounding air to minimize evaporation of the solvent or carrier for the ink and thus maintain a substantially uniform density and viscosity thereof. Since the ink is maintained in contact with a major portion of the circumference of the cylinder and plate, there is little chance that the ink will be permitted to dry Within the depressions in the plate and in effect the apparatus produces a continuous washing action on the plate due to the fact that both the chamber and the space between the blanket and plate are continuously flooded with a supply of wet ink. Of course, some of the ink spills out from the ends of the blanket into the catch basin, but by controlling the position of the trough 25, not only the chamber which supplies the ink but also the region between the blanket and cylinder up to the doctor bar can be maintained in flooded condition, effecting a substantially continuous wetting action on the printing plate.

A modification of the end seals for the ink trough is shown in Figures 6 and 7 as constituting end members 46' fixed in the ends of the trough 25 and having slots 51 opening through their edges facing the cylinder. A sealing member 47' is slidably seated in each of the slots 51, these members having arcuate edges 52 for engaging the printing surface of the cylinder 11 to seal the ends of the trough. It has been found that the sealing members 47 will remain in sealing engagement with the cylinder due to gravity but light springs may be inserted in the slots 51 for biasing the members 47' toward the cylinder. While the curvature of the edges 52 limits the range of sizes of cylinders with which they may be employed efticiently, it has been found that the same curva ture effectively seals with a surprising wide variation of cylinder sizes. F or example, the same members 47 have been successfully employed with cylinders ranging from 7 to 12% inches in diameter. These members are also formed of nylon or Mylar to prevent scratching and wear.

Although a certain specific embodiment of the invention has been shown and described, it is obvious that many modifications thereof are possible. The invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

What I claim is:

1. In combination with a rotary intaglio printing cylinder and a pressure roll for nipping paper thereagainst, a body disposed adjacent one side of said cylinder and having means for supplying ink thereto, said body being located immediately adjacent one side of the nip between said cylinder and roll, the body defining a chamber with said cylinder, a flexible sheet element extending from adjacent said body to a line disposed closely adjacent the other side of the nip between the cylinder and roll, and a doctor bar engaging said cylinder along said line, whereby ink supplied to said cylinder from said body is maintained substantially isolated from the surrounding atmosphere throughout the area of the cylinder to said line on the cylinder against which said doctor bar is engaged, said sheet element being limp, nonrigid and nonscratching to concentrically conform to said cylinder under the pressure of the ink and for cooperation with cylinders of different diameters.

2. Apparatus for supplying ink to a high speed rotary intaglio printing cylinder and for retaining the ink within the depressions of a printing plate on the cylinder throughout a major portion of the periphery of the cylinder and to a point closely adjacent the point of printing, comprising a trough-like body coextensive in length with the cylinder and having upper and lower edges disposed closely adjacent thereto, sealing means carried by the opposite ends of said body and engaging corresponding ends of said cylinder to define a substantially isolated chamber between the body and the cylinder, means for supplying ink to said chamber, and flexible sheet means extending from said body around said cylinder and in close adjacency thereto to retain the ink on the surface of said cylinder, said sheet means being limp, nonrigid and nonscratching to concentrically conform to said cylinder under the pressure of the ink and for cooperation with cylinders of difierent diameters.

3. Apparatus as defined in claim 2 wherein said sealing means includes sealing disks fixed to the opposite ends of said body, circular sealing plates peripherally engaging the inner surface of said body and carried by said discs, and resilient means yieldably urging said sealing plates against corresponding ends of said cylinder.

4. Apparatus according to claim 2 comprising a shaft journaled on said body for rotation on an axis parallel to this axis of said cylinder, one end of said sheet means being secured to said shaft, and means for rotating said shaft to wind and unwind said sheet means for effectively shortening and lengthening said sheet means to space the same closer to and further away from said cylinder and for accommodating cylinders of various size.

5. Apparatus as defined in claim 2 wherein said sealing means comprises end walls on said body and each having a slot opening through its edge facing the printing surface of the cylinder, and a sealing member loosely seated in said slot and having an arcuate edge engaging said printing surface.

6. In a rotary intaglio printing press having a rotary printing cylinder, a chamber defining body disposed at one side of said cylinder and having means for applying ink to the cylinder, sheet means extending from said body beneath said cylinder and terminating at the op posite side thereof and disposed in closely spaced relationship to the surface or" said cylinder to retain ink thereon and maintain the ink isolated from the surrounding atmosphere to prevent evaporation of ink solvents, said sheet means being limp, nonrigid and nonscratching to conform to cylinders of different diameters, and means for adjusting the spacing between said sheet and said cylinder.

7. The apparatus of claim 5 wherein said sealing means is disposed above the horizontal axis of said cylinder such that the sealing member is urged by gravity to engage the printing surface.

References Cited in the file of this patent UNITED STATES PATENTS 1,953,105 Flinker Apr. 3, 1934 1,997,612 Von Webern Apr. 16, 1935 2,272,406 Gurwick Feb. 10, 1942 2,376,620 Piazze May 22, 1945 2,377,110 Smith May 29, 1945 2,431,900 Worthington Dec. 2, 1947 2,631,532 Harless Mar. 17, 1953 

